Familial Periodic Paralysis

Familial periodic paralysis is a malady usually characterized by (1) recurrent flaccid muscular paralysis, (2) history of the disease in other members of the family, (3) depression of the level of potassium ions in the blood serum during an episode of paresis, (4) impairment of electrical excitability of the musculature, (5) impairment of deep reflexes, (6) retention of consciousness without alteration of the sensorium during the episodes, and (7) cessation or relief of attacks following the administration of salts containing potassium ions. The disorder is said1' to be hereditary in 80 per cent of the cases. It is transmitted by both sexes but males are affected twice as frequently as are females." One or more intervening generations may be free of the disorder.'6 Attacks may begin as early as at 18 months of age,9 but more often have their onset during puberty and early adult life. Attacks characteristically cease by the fourth decade. Cavare5 described familial periodic paralysis in 1853. Salts containing potassium ions were employed therapeutically by Buzzard4 in 1901 and by Mitchell'9 in 1902. In 1934, Biemond and Daniels,3 and in 1935, Walker,28 observed that during the attacks of paralysis the serum potassium ion level may be depressed below the normal levels of approximately 18 to 25 mg. per cent. In 1937 Aitken, Allott, Castleden, and Walker' and in 1938, Pudenz2' and Allott and McArdle2 related the attacks to low serum potassium and clearly established the efficacy of potassium salt therapy. Attacks usually occur at night.' They are precipitated by the local application of cold,82 by glucose," 13, 21,.23, 26, 29, 30, 31 by epinephrine, 21 26 by water diuresis,7 and by insulin with or without glu-